agpm-cli 0.4.14

//! Error handling for AGPM
//!
//! This module provides comprehensive error types and user-friendly error reporting for the
//! AGPM package manager. The error system is designed around two core principles:
//! 1. **Strongly-typed errors** for precise error handling in code
//! 2. **User-friendly messages** with actionable suggestions for CLI users
//!
//! # Architecture
//!
//! The error system consists of two main types:
//! - [`AgpmError`] - Enumerated error types for all failure cases in AGPM
//! - [`ErrorContext`] - Wrapper that adds user-friendly messages and suggestions
//!
//! # Error Categories
//!
//! AGPM errors are organized into several categories:
//! - **Git Operations**: [`AgpmError::GitNotFound`], [`AgpmError::GitCommandError`], etc.
//! - **File System**: [`AgpmError::FileSystemError`], [`AgpmError::PermissionDenied`], etc.
//! - **Configuration**: [`AgpmError::ManifestNotFound`], [`AgpmError::ManifestParseError`], etc.
//! - **Dependencies**: [`AgpmError::CircularDependency`], [`AgpmError::DependencyNotMet`], etc.
//! - **Resources**: [`AgpmError::ResourceNotFound`], [`AgpmError::InvalidResource`], etc.
//!
//! # Error Conversion and Context
//!
//! Common standard library errors are automatically converted to AGPM errors:
//! - [`std::io::Error`] → [`AgpmError::IoError`]
//! - [`toml::de::Error`] → [`AgpmError::TomlError`]
//! - [`semver::Error`] → [`AgpmError::SemverError`]
//!
//! Convert errors into user-friendly format with
//! contextual suggestions.
//!
//! # Examples
//!
//! ## Basic Error Handling
//!
//! ```rust,no_run
//! use agpm_cli::core::{AgpmError, ErrorContext};
//!
//! fn handle_git_operation() -> Result<(), AgpmError> {
//!     // Simulate a git operation failure
//!     Err(AgpmError::GitNotFound)
//! }
//!
//! match handle_git_operation() {
//!     Ok(_) => println!("Success!"),
//!     Err(e) => {
//!         let ctx = ErrorContext::new(e)
//!             .with_suggestion("Install git from https://git-scm.com/")
//!             .with_details("AGPM requires git for repository operations");
//!         ctx.display(); // Shows colored error with suggestions
//!     }
//! }
//! ```
//!
//! ## Creating Error Context Manually
//!
//! ```rust,no_run
//! use agpm_cli::core::{AgpmError, ErrorContext};
//!
//! let error = AgpmError::ManifestNotFound;
//! let context = ErrorContext::new(error)
//!     .with_suggestion("Create a agpm.toml file in your project directory")
//!     .with_details("AGPM searches for agpm.toml in current and parent directories");
//!
//! // Display with colors in terminal
//! context.display();
//!
//! // Or get as string for logging
//! let message = format!("{}", context);
//! ```
//!
//! ## Error Recovery Patterns
//!
//! ```rust,no_run
//! use agpm_cli::core::{AgpmError, ErrorContext};
//!
//! fn install_dependency(name: &str) -> Result<(), AgpmError> {
//!     // Try installation
//!     match perform_installation(name) {
//!         Ok(()) => Ok(()),
//!         Err(e) => {
//!             // Convert to user-friendly error for CLI display
//!             let friendly = ErrorContext::new(e)
//!                 .with_suggestion(format!("Check the dependency name '{}' and try again", name))
//!                 .with_details("AGPM will attempt to install the dependency and its requirements");
//!             friendly.display(); // Shows colored error with suggestions
//!             Err(AgpmError::Other { message: "Installation failed".to_string() })
//!         }
//!     }
//! }
//!
//! fn perform_installation(_name: &str) -> Result<(), AgpmError> {
//!     // Implementation would go here
//!     Ok(())
//! }
//! ```

use colored::Colorize;
use std::fmt;
use thiserror::Error;

/// The main error type for AGPM operations
///
/// This enum represents all possible errors that can occur during AGPM operations.
/// Each variant is designed to provide specific context about the failure and enable
/// appropriate error handling strategies.
///
/// # Design Philosophy
///
/// - **Specific Error Types**: Each error variant represents a specific failure mode
/// - **Rich Context**: Errors include relevant details like file paths, URLs, and reasons
/// - **User-Friendly**: Error messages are written for end users, not just developers
/// - **Actionable**: Most errors provide clear guidance on how to resolve the issue
///
/// # Error Categories
///
/// ## Git Operations
/// - [`GitNotFound`] - Git executable not available
/// - [`GitCommandError`] - Git command execution failed
/// - [`GitAuthenticationFailed`] - Git authentication problems
/// - [`GitCloneFailed`] - Repository cloning failed
/// - [`GitCheckoutFailed`] - Git checkout operation failed
///
/// ## File System Operations  
/// - [`FileSystemError`] - General file system operations
/// - [`PermissionDenied`] - Insufficient permissions
/// - [`DirectoryNotEmpty`] - Directory contains files when empty expected
/// - [`IoError`] - Standard I/O errors from [`std::io::Error`]
///
/// ## Configuration and Parsing
/// - [`ManifestNotFound`] - agpm.toml file missing
/// - [`ManifestParseError`] - Invalid TOML syntax in manifest
/// - [`ManifestValidationError`] - Manifest content validation failed
/// - [`LockfileParseError`] - Invalid lockfile format
/// - [`InvalidLockfileError`] - Invalid lockfile that can be automatically regenerated
/// - [`ConfigError`] - Configuration file issues
/// - [`TomlError`] - TOML parsing errors from [`toml::de::Error`]
/// - [`TomlSerError`] - TOML serialization errors from [`toml::ser::Error`]
///
/// ## Resource Management
/// - [`ResourceNotFound`] - Named resource doesn't exist
/// - [`ResourceFileNotFound`] - Resource file missing from repository
/// - [`InvalidResourceType`] - Unknown resource type specified
/// - [`InvalidResourceStructure`] - Resource content is malformed
/// - [`InvalidResource`] - Resource validation failed
/// - [`AlreadyInstalled`] - Resource already exists
///
/// ## Dependency Resolution
/// - [`CircularDependency`] - Dependency cycle detected
/// - [`DependencyResolutionFailed`] - Cannot resolve dependencies
/// - [`DependencyNotMet`] - Version constraint not satisfied
/// - [`InvalidDependency`] - Malformed dependency specification
/// - [`InvalidVersionConstraint`] - Invalid version format
/// - [`VersionNotFound`] - Requested version doesn't exist
/// - [`SemverError`] - Semantic version parsing from [`semver::Error`]
///
/// ## Source Management
/// - [`SourceNotFound`] - Named source not defined
/// - [`SourceUnreachable`] - Cannot connect to source repository
///
/// ## Platform and Network
/// - [`NetworkError`] - Network connectivity issues
/// - [`PlatformNotSupported`] - Operation not supported on current platform
/// - [`ChecksumMismatch`] - File integrity verification failed
///
/// # Examples
///
/// ## Pattern Matching on Errors
///
/// ```rust,no_run
/// use agpm_cli::core::AgpmError;
///
/// fn handle_error(error: AgpmError) {
///     match error {
///         AgpmError::GitNotFound => {
///             eprintln!("Please install git to use AGPM");
///             std::process::exit(1);
///         }
///         AgpmError::ManifestNotFound => {
///             eprintln!("Run 'agpm init' to create a manifest file");
///         }
///         AgpmError::NetworkError { operation, .. } => {
///             eprintln!("Network error during {}: check your connection", operation);
///         }
///         _ => {
///             eprintln!("Unexpected error: {}", error);
///         }
///     }
/// }
/// ```
///
/// ## Creating Specific Errors
///
/// ```rust,no_run
/// use agpm_cli::core::AgpmError;
///
/// // Create a git command error with context
/// let error = AgpmError::GitCommandError {
///     operation: "clone".to_string(),
///     stderr: "repository not found".to_string(),
/// };
///
/// // Create a resource not found error
/// let error = AgpmError::ResourceNotFound {
///     name: "my-agent".to_string(),
/// };
///
/// // Create a version constraint error
/// let error = AgpmError::InvalidVersionConstraint {
///     constraint: "~1.x.y".to_string(),
/// };
/// ```
///
/// [`GitNotFound`]: AgpmError::GitNotFound
/// [`GitCommandError`]: AgpmError::GitCommandError
/// [`GitAuthenticationFailed`]: AgpmError::GitAuthenticationFailed
/// [`GitCloneFailed`]: AgpmError::GitCloneFailed
/// [`GitCheckoutFailed`]: AgpmError::GitCheckoutFailed
/// [`FileSystemError`]: AgpmError::FileSystemError
/// [`PermissionDenied`]: AgpmError::PermissionDenied
/// [`DirectoryNotEmpty`]: AgpmError::DirectoryNotEmpty
/// [`IoError`]: AgpmError::IoError
/// [`ManifestNotFound`]: AgpmError::ManifestNotFound
/// [`ManifestParseError`]: AgpmError::ManifestParseError
/// [`ManifestValidationError`]: AgpmError::ManifestValidationError
/// [`LockfileParseError`]: AgpmError::LockfileParseError
/// [`InvalidLockfileError`]: AgpmError::InvalidLockfileError
/// [`ConfigError`]: AgpmError::ConfigError
/// [`TomlError`]: AgpmError::TomlError
/// [`TomlSerError`]: AgpmError::TomlSerError
/// [`ResourceNotFound`]: AgpmError::ResourceNotFound
/// [`ResourceFileNotFound`]: AgpmError::ResourceFileNotFound
/// [`InvalidResourceType`]: AgpmError::InvalidResourceType
/// [`InvalidResourceStructure`]: AgpmError::InvalidResourceStructure
/// [`InvalidResource`]: AgpmError::InvalidResource
/// [`AlreadyInstalled`]: AgpmError::AlreadyInstalled
/// [`CircularDependency`]: AgpmError::CircularDependency
/// [`DependencyResolutionFailed`]: AgpmError::DependencyResolutionFailed
/// [`DependencyNotMet`]: AgpmError::DependencyNotMet
/// [`InvalidDependency`]: AgpmError::InvalidDependency
/// [`InvalidVersionConstraint`]: AgpmError::InvalidVersionConstraint
/// [`VersionNotFound`]: AgpmError::VersionNotFound
/// [`SemverError`]: AgpmError::SemverError
/// [`SourceNotFound`]: AgpmError::SourceNotFound
/// [`SourceUnreachable`]: AgpmError::SourceUnreachable
/// [`NetworkError`]: AgpmError::NetworkError
/// [`PlatformNotSupported`]: AgpmError::PlatformNotSupported
/// [`ChecksumMismatch`]: AgpmError::ChecksumMismatch
#[derive(Error, Debug)]
pub enum AgpmError {
    /// Git operation failed during execution
    ///
    /// This error occurs when a git command returns a non-zero exit code.
    /// Common causes include network issues, authentication problems, or
    /// invalid git repository states.
    ///
    /// # Fields
    /// - `operation`: The git operation that failed (e.g., "clone", "fetch", "checkout")
    /// - `stderr`: The error output from the git command
    #[error("Git operation failed: {operation}\n{stderr}")]
    GitCommandError {
        /// The git operation that failed (e.g., "clone", "fetch", "checkout")
        operation: String,
        /// The error output from the git command
        stderr: String,
    },

    /// Git executable not found in PATH
    ///
    /// This error occurs when AGPM cannot locate the `git` command in the system PATH.
    /// AGPM requires git to be installed and available for repository operations.
    ///
    /// Common solutions:
    /// - Install git from <https://git-scm.com/>
    /// - Use a package manager: `brew install git`, `apt install git`, etc.
    /// - Ensure git is in your PATH environment variable
    #[error("Git is not installed or not found in PATH")]
    GitNotFound,

    /// Git repository is invalid or corrupted
    ///
    /// This error occurs when a directory exists but doesn't contain a valid
    /// git repository structure (missing .git directory or corrupted).
    ///
    /// # Fields
    /// - `path`: The path that was expected to contain a git repository
    #[error("Not a valid git repository: {path}")]
    GitRepoInvalid {
        /// The path that was expected to contain a git repository
        path: String,
    },

    /// Git authentication failed for repository access
    ///
    /// This error occurs when git cannot authenticate with a remote repository.
    /// Common for private repositories or when credentials are missing/expired.
    ///
    /// # Fields
    /// - `url`: The repository URL that failed authentication
    #[error("Git authentication failed for repository: {url}")]
    GitAuthenticationFailed {
        /// The repository URL that failed authentication
        url: String,
    },

    /// Git repository clone failed
    #[error("Failed to clone repository: {url}\n{reason}")]
    GitCloneFailed {
        /// The repository URL that failed to clone
        url: String,
        /// The reason for the clone failure
        reason: String,
    },

    /// Git checkout failed
    #[error("Failed to checkout reference '{reference}' in repository")]
    GitCheckoutFailed {
        /// The git reference (branch, tag, or commit) that failed to checkout
        reference: String,
        /// The reason for the checkout failure
        reason: String,
    },

    /// Configuration error
    #[error("Configuration error: {message}")]
    ConfigError {
        /// Description of the configuration error
        message: String,
    },

    /// Manifest file (agpm.toml) not found
    ///
    /// This error occurs when AGPM cannot locate a agpm.toml file in the current
    /// directory or any parent directory up to the filesystem root.
    ///
    /// AGPM searches for agpm.toml starting from the current working directory
    /// and walking up the directory tree, similar to how git searches for .git.
    #[error("Manifest file agpm.toml not found in current directory or any parent directory")]
    ManifestNotFound,

    /// Manifest parsing error
    #[error("Invalid manifest file syntax in {file}")]
    ManifestParseError {
        /// Path to the manifest file that failed to parse
        file: String,
        /// Specific reason for the parsing failure
        reason: String,
    },

    /// Manifest validation error
    #[error("Manifest validation failed: {reason}")]
    ManifestValidationError {
        /// Reason why manifest validation failed
        reason: String,
    },

    /// Lockfile parsing error
    #[error("Invalid lockfile syntax in {file}")]
    LockfileParseError {
        /// Path to the lockfile that failed to parse
        file: String,
        /// Specific reason for the parsing failure
        reason: String,
    },

    /// Invalid lockfile that can be automatically regenerated
    #[error(
        "Invalid or corrupted lockfile detected: {file}\n\n{reason}\n\nNote: The lockfile format is not yet stable as this is beta software."
    )]
    InvalidLockfileError {
        /// Path to the invalid lockfile
        file: String,
        /// Specific reason why the lockfile is invalid
        reason: String,
        /// Whether automatic regeneration is offered
        can_regenerate: bool,
    },

    /// Resource not found
    #[error("Resource '{name}' not found")]
    ResourceNotFound {
        /// Name of the resource that could not be found
        name: String,
    },

    /// Resource file not found in repository
    #[error("Resource file '{path}' not found in source '{source_name}'")]
    ResourceFileNotFound {
        /// Path to the resource file within the source repository
        path: String,
        /// Name of the source repository where the file was expected
        source_name: String,
    },

    /// Source repository not found
    #[error("Source repository '{name}' not defined in manifest")]
    SourceNotFound {
        /// Name of the source repository that is not defined
        name: String,
    },

    /// Source repository unreachable
    #[error("Cannot reach source repository '{name}' at {url}")]
    SourceUnreachable {
        /// Name of the source repository
        name: String,
        /// URL of the unreachable repository
        url: String,
    },

    /// Invalid version constraint
    #[error("Invalid version constraint: {constraint}")]
    InvalidVersionConstraint {
        /// The invalid version constraint string
        constraint: String,
    },

    /// Version not found
    #[error("Version '{version}' not found for resource '{resource}'")]
    VersionNotFound {
        /// Name of the resource for which the version was not found
        resource: String,
        /// The version string that could not be found
        version: String,
    },

    /// Resource already installed
    #[error("Resource '{name}' is already installed")]
    AlreadyInstalled {
        /// Name of the resource that is already installed
        name: String,
    },

    /// Invalid resource type
    #[error("Invalid resource type: {resource_type}")]
    InvalidResourceType {
        /// The invalid resource type that was specified
        resource_type: String,
    },

    /// Invalid resource structure
    #[error("Invalid resource structure in '{file}': {reason}")]
    InvalidResourceStructure {
        /// Path to the file with invalid resource structure
        file: String,
        /// Reason why the resource structure is invalid
        reason: String,
    },

    /// Circular dependency detected in dependency graph
    ///
    /// This error occurs when resources depend on each other in a cycle,
    /// making it impossible to determine installation order.
    ///
    /// Example: A depends on B, B depends on C, C depends on A
    ///
    /// # Fields
    /// - `chain`: The dependency chain showing the circular reference
    #[error("Circular dependency detected: {chain}")]
    CircularDependency {
        /// String representation of the circular dependency chain
        chain: String,
    },

    /// Dependency resolution failed
    #[error("Cannot resolve dependencies: {reason}")]
    DependencyResolutionFailed {
        /// Reason why dependency resolution failed
        reason: String,
    },

    /// Dependency resolution mismatch between declared and resolved dependencies
    ///
    /// This error occurs when a resource declares N dependencies in its frontmatter
    /// but only M dependencies (where M < N) were successfully resolved. This indicates
    /// a bug in the dependency resolution process, likely due to path normalization issues.
    ///
    /// # Fields
    /// - `resource`: Name of the resource with the mismatch
    /// - `declared_count`: Number of dependencies declared in frontmatter
    /// - `resolved_count`: Number of dependencies actually resolved
    /// - `declared_deps`: List of (resource_type, path) for declared dependencies
    #[error("Dependency resolution mismatch for resource '{resource}'")]
    DependencyResolutionMismatch {
        /// Name of the resource with the dependency mismatch
        resource: String,
        /// Number of dependencies declared in frontmatter
        declared_count: usize,
        /// Number of dependencies actually resolved
        resolved_count: usize,
        /// List of declared dependencies as (resource_type, path) tuples
        declared_deps: Vec<(String, String)>,
    },

    /// Network error
    #[error("Network error: {operation}")]
    NetworkError {
        /// The network operation that failed
        operation: String,
        /// Reason for the network failure
        reason: String,
    },

    /// File system error
    #[error("File system error: {operation}: {path}")]
    FileSystemError {
        /// The file system operation that failed
        operation: String,
        /// Path where the file system error occurred
        path: String,
    },

    /// Permission denied
    #[error("Permission denied: {operation}: {path}")]
    PermissionDenied {
        /// The operation that was denied due to insufficient permissions
        operation: String,
        /// Path where permission was denied
        path: String,
    },

    /// Directory not empty
    #[error("Directory is not empty: {path}")]
    DirectoryNotEmpty {
        /// Path to the directory that is not empty
        path: String,
    },

    /// Invalid dependency specification
    #[error("Invalid dependency specification for '{name}': {reason}")]
    InvalidDependency {
        /// Name of the invalid dependency
        name: String,
        /// Reason why the dependency specification is invalid
        reason: String,
    },

    /// Invalid resource content
    #[error("Invalid resource content in '{name}': {reason}")]
    InvalidResource {
        /// Name of the invalid resource
        name: String,
        /// Reason why the resource content is invalid
        reason: String,
    },

    /// Dependency not met
    #[error("Dependency '{name}' requires version {required}, but {found} was found")]
    DependencyNotMet {
        /// Name of the dependency that is not satisfied
        name: String,
        /// The required version constraint
        required: String,
        /// The version that was actually found
        found: String,
    },

    /// Config file not found
    #[error("Configuration file not found: {path}")]
    ConfigNotFound {
        /// Path to the configuration file that was not found
        path: String,
    },

    /// Checksum mismatch
    #[error("Checksum mismatch for resource '{name}': expected {expected}, got {actual}")]
    ChecksumMismatch {
        /// Name of the resource with checksum mismatch
        name: String,
        /// The expected checksum value
        expected: String,
        /// The actual checksum that was computed
        actual: String,
    },

    /// Platform not supported
    #[error("Operation not supported on this platform: {operation}")]
    PlatformNotSupported {
        /// The operation that is not supported on this platform
        operation: String,
    },

    /// IO error
    #[error("IO error: {0}")]
    IoError(#[from] std::io::Error),

    /// TOML parsing error
    #[error("TOML parsing error: {0}")]
    TomlError(#[from] toml::de::Error),

    /// TOML serialization error
    #[error("TOML serialization error: {0}")]
    TomlSerError(#[from] toml::ser::Error),

    /// Semver parsing error
    #[error("Semver parsing error: {0}")]
    SemverError(#[from] semver::Error),

    /// Other error
    #[error("{message}")]
    Other {
        /// Generic error message
        message: String,
    },
}

/// Error context wrapper that provides user-friendly error information
///
/// `ErrorContext` wraps a [`AgpmError`] and adds optional user-friendly messages,
/// suggestions for resolution, and additional details. This is the primary way
/// AGPM presents errors to CLI users.
///
/// # Design Philosophy
///
/// Error contexts are designed to be:
/// - **Actionable**: Include specific suggestions for resolving the error
/// - **Informative**: Provide context about why the error occurred
/// - **Colorized**: Use terminal colors to highlight important information
/// - **Consistent**: Follow a standard format across all error types
///
/// # Display Format
///
/// When displayed, errors show:
/// 1. **Error**: The main error message in red
/// 2. **Details**: Additional context about the error in yellow (optional)
/// 3. **Suggestion**: Actionable steps to resolve the issue in green (optional)
///
/// # Examples
///
/// ## Creating Error Context
///
/// ```rust,no_run
/// use agpm_cli::core::{AgpmError, ErrorContext};
///
/// let error = AgpmError::GitNotFound;
/// let context = ErrorContext::new(error)
///     .with_suggestion("Install git from https://git-scm.com/")
///     .with_details("AGPM requires git for repository operations");
///
/// // Display to terminal with colors
/// context.display();
///
/// // Or convert to string for logging
/// let message = context.to_string();
/// ```
///
/// ## Builder Pattern Usage
///
/// ```rust,no_run
/// use agpm_cli::core::{AgpmError, ErrorContext};
///
/// let context = ErrorContext::new(AgpmError::ManifestNotFound)
///     .with_suggestion("Create a agpm.toml file in your project directory")
///     .with_details("AGPM searches current and parent directories for agpm.toml");
///
/// println!("{}", context);
/// ```
///
/// ## Quick Suggestion Creation
///
/// ```rust,no_run
/// use agpm_cli::core::ErrorContext;
///
/// // Create context with just a suggestion (useful for generic errors)
/// let context = ErrorContext::suggestion("Try running the command with --verbose");
/// ```
#[derive(Debug)]
pub struct ErrorContext {
    /// The underlying AGPM error
    pub error: AgpmError,
    /// Optional suggestion for resolving the error
    pub suggestion: Option<String>,
    /// Optional additional details about the error
    pub details: Option<String>,
}

impl ErrorContext {
    /// Create a new error context from a [`AgpmError`]
    ///
    /// This creates a basic error context with no additional suggestions or details.
    /// Use the builder methods [`with_suggestion`] and [`with_details`] to add
    /// user-friendly information.
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// use agpm_cli::core::{AgpmError, ErrorContext};
    ///
    /// let context = ErrorContext::new(AgpmError::GitNotFound);
    /// ```
    ///
    /// [`with_suggestion`]: ErrorContext::with_suggestion
    /// [`with_details`]: ErrorContext::with_details
    #[must_use]
    pub const fn new(error: AgpmError) -> Self {
        Self {
            error,
            suggestion: None,
            details: None,
        }
    }

    /// Add a suggestion for resolving the error
    ///
    /// Suggestions should be actionable steps that users can take to resolve
    /// the error. They are displayed in green in the terminal to draw attention.
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// use agpm_cli::core::{AgpmError, ErrorContext};
    ///
    /// let context = ErrorContext::new(AgpmError::GitNotFound)
    ///     .with_suggestion("Install git using 'brew install git' or visit https://git-scm.com/");
    /// ```
    pub fn with_suggestion(mut self, suggestion: impl Into<String>) -> Self {
        self.suggestion = Some(suggestion.into());
        self
    }

    /// Add additional details explaining the error
    ///
    /// Details provide context about why the error occurred or what it means.
    /// They are displayed in yellow in the terminal to provide additional context
    /// without being as prominent as the main error or suggestion.
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// use agpm_cli::core::{AgpmError, ErrorContext};
    ///
    /// let context = ErrorContext::new(AgpmError::ManifestNotFound)
    ///     .with_details("AGPM looks for agpm.toml in current directory and parent directories");
    /// ```
    pub fn with_details(mut self, details: impl Into<String>) -> Self {
        self.details = Some(details.into());
        self
    }

    /// Display the error context to stderr with terminal colors
    ///
    /// This method prints the error, details, and suggestion to stderr using
    /// color coding:
    /// - Error message: Red and bold
    /// - Details: Yellow
    /// - Suggestion: Green
    ///
    /// This is the primary way AGPM presents errors to users in the CLI.
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// use agpm_cli::core::{AgpmError, ErrorContext};
    ///
    /// let context = ErrorContext::new(AgpmError::GitNotFound)
    ///     .with_suggestion("Install git from https://git-scm.com/")
    ///     .with_details("AGPM requires git for repository operations");
    ///
    /// context.display(); // Prints colored error to stderr
    /// ```
    pub fn display(&self) {
        eprintln!("{}: {}", "error".red().bold(), self.error);

        if let Some(details) = &self.details {
            eprintln!("{}: {}", "details".yellow(), details);
        }

        if let Some(suggestion) = &self.suggestion {
            eprintln!("{}: {}", "suggestion".green(), suggestion);
        }
    }
}

impl fmt::Display for ErrorContext {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.error)?;

        if let Some(details) = &self.details {
            write!(f, "\nDetails: {details}")?;
        }

        if let Some(suggestion) = &self.suggestion {
            write!(f, "\nSuggestion: {suggestion}")?;
        }

        Ok(())
    }
}

impl std::error::Error for ErrorContext {}

/// Extension trait for converting [`AgpmError`] to [`anyhow::Error`] with context
///
/// This trait provides a method to convert AGPM-specific errors into generic
/// [`anyhow::Error`] instances while preserving user-friendly context information.
///
/// # Examples
///
/// ```rust,no_run
/// use agpm_cli::core::{AgpmError, ErrorContext, IntoAnyhowWithContext};
///
/// let error = AgpmError::GitNotFound;
/// let context = ErrorContext::new(AgpmError::Other { message: "dummy".to_string() })
///     .with_suggestion("Install git");
///
/// let anyhow_error = error.into_anyhow_with_context(context);
/// ```
pub trait IntoAnyhowWithContext {
    /// Convert the error to an [`anyhow::Error`] with the provided context
    fn into_anyhow_with_context(self, context: ErrorContext) -> anyhow::Error;
}

impl IntoAnyhowWithContext for AgpmError {
    fn into_anyhow_with_context(self, context: ErrorContext) -> anyhow::Error {
        anyhow::Error::new(ErrorContext {
            error: self,
            suggestion: context.suggestion,
            details: context.details,
        })
    }
}

impl ErrorContext {
    /// Create an [`ErrorContext`] with only a suggestion (no specific error)
    ///
    /// This is useful for generic errors where you want to provide a suggestion
    /// but don't have a specific [`AgpmError`] variant.
    ///
    /// # Examples
    ///
    /// ```rust,no_run
    /// use agpm_cli::core::ErrorContext;
    ///
    /// let context = ErrorContext::suggestion("Try running with --verbose for more information");
    /// context.display();
    /// ```
    pub fn suggestion(suggestion: impl Into<String>) -> Self {
        Self {
            error: AgpmError::Other {
                message: String::new(),
            },
            suggestion: Some(suggestion.into()),
            details: None,
        }
    }
}

/// Convert any error to a user-friendly [`ErrorContext`] with actionable suggestions
///
/// This function is the main entry point for converting arbitrary errors into
/// user-friendly error messages for CLI display. It recognizes common error types
/// and provides appropriate context and suggestions.
///
/// # Error Recognition
///
/// The function recognizes and provides specific handling for:
/// - [`AgpmError`] variants with tailored suggestions
/// - [`std::io::Error`] with filesystem-specific guidance
/// - [`toml::de::Error`] with TOML syntax help
/// - Generic errors with basic context
///
/// # Examples
///
/// ## Converting AGPM Errors
///
/// ```rust,no_run
/// use agpm_cli::core::{AgpmError, ErrorContext};
///
/// let error = AgpmError::GitNotFound;
/// let anyhow_error = anyhow::Error::from(error);
/// let context = anyhow_error.context("Operation failed");
///
/// context.display(); // Shows git installation suggestions
/// ```
///
/// ## Converting IO Errors
///
/// ```rust,no_run
/// use agpm_cli::core::ErrorContext;
/// use std::io::{Error, ErrorKind};
///
/// let io_error = Error::new(ErrorKind::PermissionDenied, "access denied");
/// let anyhow_error = anyhow::Error::from(io_error);
/// let context = anyhow_error.context("Operation failed");
///
/// context.display(); // Shows permission-related suggestions
/// ```
///
/// ## Converting Generic Errors
///
/// ```rust,no_run
/// use agpm_cli::core::ErrorContext;
///
/// let error = anyhow::anyhow!("Something went wrong");
/// let context = ErrorContext::new(error);
///
/// context.display(); // Shows the error with generic formatting
/// ```
///
#[cfg(test)]
mod tests {
    use super::*;
    use crate::core::error_formatting::create_error_context;

    #[test]
    fn test_error_display() {
        let error = AgpmError::GitNotFound;
        assert_eq!(error.to_string(), "Git is not installed or not found in PATH");

        let error = AgpmError::ResourceNotFound {
            name: "test".to_string(),
        };
        assert_eq!(error.to_string(), "Resource 'test' not found");

        let error = AgpmError::InvalidVersionConstraint {
            constraint: "bad-version".to_string(),
        };
        assert_eq!(error.to_string(), "Invalid version constraint: bad-version");

        let error = AgpmError::GitCommandError {
            operation: "clone".to_string(),
            stderr: "repository not found".to_string(),
        };
        assert_eq!(error.to_string(), "Git operation failed: clone\nrepository not found");
    }

    #[test]
    fn test_error_context() {
        let ctx = ErrorContext::new(AgpmError::GitNotFound)
            .with_suggestion("Install git using your package manager")
            .with_details("Git is required for AGPM to function");

        assert_eq!(ctx.suggestion, Some("Install git using your package manager".to_string()));
        assert_eq!(ctx.details, Some("Git is required for AGPM to function".to_string()));
    }

    #[test]
    fn test_error_context_display() {
        let ctx = ErrorContext::new(AgpmError::GitNotFound).with_suggestion("Install git");

        let display = format!("{ctx}");
        assert!(display.contains("Git is not installed or not found in PATH"));
    }

    #[test]
    fn test_from_semver_error() {
        let result = semver::Version::parse("invalid-version");
        if let Err(e) = result {
            let agpm_error = AgpmError::from(e);
            match agpm_error {
                AgpmError::SemverError(_) => {}
                _ => panic!("Expected SemverError"),
            }
        }
    }

    #[test]
    fn test_error_display_all_variants() {
        // Test display for various error variants
        let errors = vec![
            AgpmError::GitRepoInvalid {
                path: "/test/path".to_string(),
            },
            AgpmError::GitCheckoutFailed {
                reference: "main".to_string(),
                reason: "not found".to_string(),
            },
            AgpmError::ConfigError {
                message: "config issue".to_string(),
            },
            AgpmError::ManifestValidationError {
                reason: "invalid format".to_string(),
            },
            AgpmError::LockfileParseError {
                file: "agpm.lock".to_string(),
                reason: "syntax error".to_string(),
            },
            AgpmError::ResourceFileNotFound {
                path: "test.md".to_string(),
                source_name: "source".to_string(),
            },
            AgpmError::DirectoryNotEmpty {
                path: "/some/dir".to_string(),
            },
            AgpmError::InvalidDependency {
                name: "dep".to_string(),
                reason: "bad format".to_string(),
            },
            AgpmError::DependencyNotMet {
                name: "dep".to_string(),
                required: "v1.0".to_string(),
                found: "v2.0".to_string(),
            },
            AgpmError::ConfigNotFound {
                path: "/config/path".to_string(),
            },
            AgpmError::PlatformNotSupported {
                operation: "test op".to_string(),
            },
        ];

        for error in errors {
            let display = format!("{error}");
            assert!(!display.is_empty());
        }
    }

    #[test]
    fn test_create_error_context_git_operations() {
        // Test different git operations
        let operations = vec![
            ("fetch", "internet connection"),
            ("checkout", "branch, tag"),
            ("pull", "git configuration"),
        ];

        for (op, expected_text) in operations {
            let ctx = create_error_context(&AgpmError::GitCommandError {
                operation: op.to_string(),
                stderr: "error".to_string(),
            });
            assert!(ctx.suggestion.is_some());
            assert!(ctx.suggestion.unwrap().to_lowercase().contains(expected_text));
        }
    }

    #[test]
    fn test_create_error_context_resource_file_not_found() {
        let ctx = create_error_context(&AgpmError::ResourceFileNotFound {
            path: "agents/test.md".to_string(),
            source_name: "official".to_string(),
        });
        assert!(ctx.suggestion.is_some());
        let suggestion = ctx.suggestion.unwrap();
        assert!(suggestion.contains("agents/test.md"));
        assert!(suggestion.contains("official"));
        assert!(ctx.details.is_some());
    }

    #[test]
    fn test_create_error_context_manifest_parse_error() {
        let ctx = create_error_context(&AgpmError::ManifestParseError {
            file: "custom.toml".to_string(),
            reason: "invalid syntax".to_string(),
        });
        assert!(ctx.suggestion.is_some());
        let suggestion = ctx.suggestion.unwrap();
        assert!(suggestion.contains("custom.toml"));
        assert!(ctx.details.is_some());
    }

    #[test]
    fn test_create_error_context_git_clone_failed() {
        let ctx = create_error_context(&AgpmError::GitCloneFailed {
            url: "https://example.com/repo.git".to_string(),
            reason: "network error".to_string(),
        });
        assert!(ctx.suggestion.is_some());
        let suggestion = ctx.suggestion.unwrap();
        assert!(suggestion.contains("https://example.com/repo.git"));
        assert!(ctx.details.is_some());
    }
}